Redox with 3 half reactions

H+In summary, the conversation discusses the balancing of a redox equation involving the reactants KBrO2, KI, and HBr and the products KBr, I2, and H2O. The equations given are multiplied and combined to show how the equation can be balanced. The question is also raised about the lack of examples using three half reactions in textbooks.
  • #1
fish
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0
KBrO2 + KI + HBr ---> KBr + I2 + H2O

eq1
KBrO2 ---> KBr
4e- + 4H+ +KBrO2 ---> KBr + 2H2O

eq2
2KI ---> I2 + 2K+ + 2e-
4KI ---> 2I2 + 4K+ + 4e-

eq3
HBr ---> KBr
K+ + HBr ---> KBr + H+

since the charges in eq3 are +1=+1
you don't have to multiply this equation by 4 do you?

3H+ + KBrO2 + 4KI + HBr ---> 2KBr + 2H2O + 2I2 + 3K+


Haven't been able to find any examples or problems with
redox using 3 half reactions in any of my textbooks. Why
wouldn't they put a few in there?
 
Last edited:
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  • #2
eq3
HBr ---> KBr
K+ + HBr ---> KBr + H+

multiply eq3 by 4 so K+ will cancel

4K+ + 4HBr ---> 4KBr + 4H+

adding all three:

KBrO2 + 4KI + 4HBr ---> 5KBr + 2H2O + 2I2
 
Last edited:
  • #3


There could be a few reasons why you haven't found examples or problems with redox reactions using 3 half reactions in your textbooks. One possibility is that these types of reactions may be more complex and therefore not typically included in introductory chemistry textbooks. Another reason could be that these types of reactions are not commonly encountered in everyday chemistry applications. However, it is important to understand the concept of redox reactions and how to balance them using half reactions, as it is a fundamental concept in chemistry and may be encountered in more advanced studies or in real-life scenarios. It is always helpful to practice and familiarize yourself with different types of reactions, including those with 3 half reactions, to strengthen your understanding and problem-solving skills. You can also look for additional resources or ask your instructor for more examples or practice problems.
 

1. What is a redox reaction?

A redox reaction, short for reduction-oxidation reaction, is a chemical reaction in which there is a transfer of electrons between two species. One species loses electrons (oxidation) while the other gains electrons (reduction).

2. What are half reactions?

Half reactions are the individual reactions that make up a redox reaction. They represent either the oxidation or reduction process and involve the transfer of electrons.

3. How many half reactions are involved in a redox reaction?

A redox reaction typically involves three half reactions: one for the oxidation process, one for the reduction process, and one for the overall reaction.

4. What is the purpose of balancing half reactions?

The purpose of balancing half reactions is to ensure that the number of electrons transferred is equal on both sides of the equation. This maintains the conservation of charge and allows the overall redox reaction to be balanced.

5. How can I determine the oxidizing and reducing agents in a redox reaction with 3 half reactions?

The species that is reduced is the oxidizing agent, as it is causing the oxidation of the other species. The species that is oxidized is the reducing agent, as it is causing the reduction of the other species. In a redox reaction with 3 half reactions, the species involved in the overall reaction will be the reducing agent for one half reaction and the oxidizing agent for the other half reaction.

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